Packaging machine and method

ABSTRACT

A machine and method for packaging cheese are disclosed as including apparatus having a four unit die for enabling the vacuum packaging of four cheese packages at any one time. The packages are formed by top and bottom plastic webs which are first partially sealed, then evacuated, then finally sealed, partially cut, examined for leaks, and then fully cut and separated to eliminate defective packages. The examination for leaks is accomplished by a novel leak detection system including apparatus for sensing package leaks after final seal has been accomplished.

United States Patent 1 OLenick etal. July 10, 1973 [54] PACKAGINGMACHINE AND METHOD 3,592,049 7/1971 Johanski 53/53 X [75] Inventors:Anthony J. OLenick, Fairlawn;

Douglas P. Roome, Cedar Grove, Prima ry Exammer-Trav1s S. McGehee bothof NJ.; Rudolf A. Spyra, A A t & R th t Crystal Lake; Ihor Wyslotsky,omey ms er 0 s em Country Club Hills, both of I11. [73] Assignee:Standard Packaging Corporation,

New York, N.Y. [57] ABSTRACT [22] File J ne 8, 1971 A machine and methodfor packaging cheese are dis 2 A L N t 157 228 closed as includingapparatus having a four unit die for 1 pp 0 enabling the vacuumpackaging of four cheese packages at any one time. The packages areformed by top Cl 53/22 5 and bottom plastic webs which are firstpartially sealed,

1 12 73/493 then evacuated, then finally sealed, partially cut, exam- [5l 1 I131. ined for leaks and then cut and eparated to elimi- Field ofSearch 3/ nate defective packages. The examination for leaks isaccomplished by a novel leak detection system including apparatus forsensing package leaks after final seal [56] Refere ces Cited has beenaccomplished.

UNITED STATES PATENTS 3,591,944 7/1971 Wilcox 53/53 X 4 Claims, 15Drawing Figures PATENIED JUL 1 0 I973 SHEET 3 0F 8 PATENIEB JUL 1 0 I9753,744,219

' sum 5 or. a

FIG. 9.

PAIENIED JUL 1 0 I973 SHEET 6 0F 8 FIG. H.

i an! UIIILI C, Julhq mill-W I III lIIIIEL illllll' COME AIR PACKAGINGMACHINE AND METHODv This invention relates primarily to processingmachines and methods and more particularly to such machines and methodsapplicable to perishable products and the like.

A multitude of prior art machines and methods have been devised forautomatically packaging products including those which form packagesfrom heat-sealable flexible packaging material. Such packages have foundwide acceptance in the food packaging field because of the extendedshelf life afforded to the packaged product by use of such materials.For instance, meats, cheeses, nuts and dried fruits have particularlybenefited from such packaging in that these food products must beprotected from oxidizing influences such as atmospheric oxygen and mustbe vacuum sealed for preservation purposes.

Prior art apparatus has included means for conveying a plurality ofpackages, for example packages of cheese, through various operationstations. For instance, a first station includes means for forming twocheese packages at any one time, the packages having top and bottom heatscalable web members conveyed along with the packages through variousoperation stations. A second station includes means for sealing the topand bottom webs and the next station includes means for cutting andseparating the formed packages. Various leak detection systems have beenemployed with such prior art systems, but apparatus for such detectionis usually separate from the general packaging apparatus. Such detectionapparatus has also required an input of only individual packages whichdictates the timing and placement of the separating mechanism for theindividual packages in the packaging machine. Also, when a defectivepackage is sensed by such prior art mechanisms, hand-sorting techniquesare commonly used to separate the good packages from the bad.

Accordingly, a primary object of the present invention is to provide afully automatic, continuous packaging, evacuating, leak detection andsorting apparatus and method to overcome the difficulties experiencedwith prior art apparatus and methods.

A further and more particular object of the present inventionis toprovide a continuous packaging apparatus and method that includes meansfor handling four packages at any one operational station of theapparatus.

A still further object is to provide an apparatus and method useful inthe packaging of perishable foodstuff and the like which includes anovel leak detection system, which automatically, during the packagingprocess, detects defective packages and programs the separation thereoffrom the packages without defects.

These and other objects of the present invention are accomplished in oneillustrative embodiment thereof which features an apparatus and methodfor forming packages. Heat-scalable flexible packaging webs are movedover a die, to form a plurality of attached receptacles for receivingthe product to be packaged. The bottom web is formed into a bottom wallfor such receptacles by a bottom vacuum with a top air pressure assist.The food product is then loaded into the receptacles and covered by anunformed top web, after which the receptacle is partially sealed. Theforegoing method is performed at a first machine station according tothe present invention and four product receptacles are thereby provided.

The receptacles or packages are then moved along to a second stationwherein the packages are evacuated, carbon dioxide and a freon tracerare introduced to the receptacle and a-final seal of the top web to thebottom web is accomplished to seal the packages. Thus, the secondstation in the apparatus and method of the present invention provides anevacuated product chamber and the introduction of a leak detectiontracer prior to final sealing of the product receptacle.

Strippers and knives then accomplish partial separa tion of packages inpreparation for a leak detection step at a third station, and apparatusis provided for detecting any escape of the tracer introduced to thepackages.

A final station accomplishes severance into four individual packages;however, such final separation is eliminated upon a signal from the leakdetection system that a particular package is defective. This finalstation of the apparatus is capable of conveying, for furtherprocessing, only individual packages and tandem packages are therebyseparated from the non-defective individual packages. Simultaneouslywith such separation of defective from non-defective packages, a suctionsystem operates to deposit all packages and then convey only theindividual non-defective packages for further processing.

The above brief description as well as further objects, features andadvantages of the present invention will be more fully appreciated byreference to-the following detailed description of the preferred, butnonetheless illustrative embodiment when taken in conjunction with theaccompanying drawings, wherein:

FIG. 1 is an elevational view of the system apparatus according to thepresent invention showing particularly the conveyor system, thesealing,cutting and leak detection head and the product separationapparatus thereof;

FIG. 2 is a top plan view of the product separation apparatus andconveyor system;

FIG. 3 is a longitudinal sectional view of the sealing, cutting and leakdetection head useful in the apparatus according to the presentinvention and a partial view of the package conveyor system therefor;

FIG. 4 is a top plan view of packages in process (the process beinglinearly presented for clarity) showing particularly the conditionsthereof at various stages in the apparatus of the present invention;

FIG. 5 is a transverse section, taken along the line 5-5 of FIG. 4 andshowing particularly the formation of packages by the use of top andbottom webs according to the present invention as well as theconstruction of the four unit dies useful in such formation;

FIG. 6 is a sectional view taken along the line 6-6 of FIG. 3 andshowing particularly the construction of apparatus useful in evacuation,tracer filling and final hot sealing of packages at a second station ofpackaging apparatus according to the present invention;

FIG. 7 is a partial plan view of the package and package web side clampconstruction useful during the operation performed by the apparatus ofFIG. 6;

FIG. 8 is a sectional view taken along the line 8-8 of FIG. 7 andshowing particularly the evacuation and carbon dioxide and freonintroducing apparatus useful in the operations performed by theapparatus of FIG. 6 according to the present invention;

FIG. 9 is a sectional view taken along the line 9-9 of FIG. 3 andshowing particularly the leak detection and partial cutting apparatusstation according to the present invention;

FIG. 10 depicts the apparatus of FIG. 9, during the partial cuttingoperation and with a vacuum chamber formed for leak detection;

FIG. 11 is a further view of the apparatus of FIG. 9 showingparticularly the final leak detection operation wherein the package iscompletely exposed to better enable leak detection of the entire packagesurface;

FIG. 12 is a schematic representation of an entire system according tothe present invention showing particularly the leak detection system,the defective package separation system and the interconnectiontherebetween;

FIG. 13 is a sectional view taken along the line 13-13 of FIG. 1 andshowing particularly the final cutting apparatus along with thedefective product separation construction and apparatus;

FIG. 14 is a sectional view taken along the line 14-14 of FIG. 13 andshowing particularly the final cutting apparatus according to thepresent invention;

FIG. 15 is a sectional view taken along the line 15-15 of FIG. 13 andshowing a further view of the apparatus for separation of packages toenable further processing according to the present invention.

Referring to the drawings, and in particular to FIG. 1 thereof, anapparatus according to the present invention hereof is shown asincluding a machine, generally designated 10, having a machine frame 14and a movable head frame 12. A conveyor system, generally designated 16,is rotatably attached to the machine frame 14 by a shaft 14 andappropriate bearings and the like. Conveyor system 16 includes sprocket18 and conveyor member 20 in the form of a linked chain or the like.Conveyor member 20 is arranged to move about sprocket 18 such that itforms an upper run 20a and a 'lower run 20b and carries a plurality ofdie members 22 as will be more fully described hereinafter.

Attached to movable head frame 12 is a machine head 24 defining machinestations A,B,C, the function of which will be apparent by a subsequentdetailed description herein of an apparatus and method according to apreferred embodiment of the present invention Furthermore, the lower run2012 of the conveyor system defines a machine station D, whose functionit is to release all packages processed in the upper run and toselectively cut and separate such packages for further processing. Suchfurther processing is accomplished on a belt system or the like,generally designated 26 wherein individual packages 28 are conveyed indirection 30 for boxing or other further processing. The belt system 26includes belt rollers 31, about which belts 33 move and sprockets 32,about which line chain 34 moves. Belt system 26 is carried on a framemember 36 to which is pivotally attached a removal mechanism as willhereinafter be explained in detail. The removal mechanism includes arms38 and arm uprights 40, whose motion is as dictated by cam system 42 andlinks 44. Cam system 42 also provides control for the motion of movablehead frame 12 by means of link 46 and cam follower 48.

A second cam system 50,including cam 52 and cam follower 54 controls themotion ofa part of the mechanism of station B as will hereinafter beexplained and a third cam system 56, including cam 58 and cam follower60 controls the mechanism at station D of the apparatus herein. Thus, byway of general description, perishable items such as cheeses areprocessed by the apparatus of the present invention by deposit in diemembers 22 and conveyance of such die members 22 in direction 62 in theupper run 20a of a conveyor system, such that the die members pass head24 for processing. Such processing includes the formation of a package;initial sealing at station A; evacuation, the introduction of a leaktracer and final sealing at station B; partial cutting and evacuationfor leak detection at station C and conveyance to the lower run 20b ofthe conveyor system. On the lower run of the conveyor system, at stationD, the packages 28 are moved in direction 61 where final cutting isaccomplished for all packages where no leaks have been detected and allpackages are released from conveyor system 16 to belt sys-- tem 26.

Referring now to FIGS; 3 through 11(with some reference to FIG. 12), themechanism of head 24 will now be described in detail. In order to setthe background for such a description, reference will first be made toFIGS. 4 and 5 in order to describe the initial formation of packages 28for processing by the mechanism of head 24.

Die member 22 includes main body member 66 defining die cavities 68.Four such die cavities 68 are provided according to the presentinvention herein such that four cheese packages are processed at any onetime in any one of the operational stations A,B,C,D in the apparatus ofthe packaging machine. Furthermore, it is to be understood that alloperations of the apparatus of the present invention take placesimultaneously, so that while one set of four cheese packages isundergoing processing at one station, another set of four cheesepackages is undergoing other processing in another station. v

A web, generally designated '70, is conveyed onto die member 22, the webincluding top and bottom web members 70a, 70b, respectively. Bottom webmember 70b is preformed into a package bottom by simultaneous bottomsuction and top pressure so that it conforms to the die cavity 68 in diemember 22. Thereafter, a batch loader or the like (not shown) by meanswell known in the art, deposits cheese 72 onto package bottoms formed bybottom web member 70b. Top web member 70a is then conveyed (by meanswell known in the art) to cover cheese 72 and thereby form a totalpakcage for processing by an apparatus and method according to thepresent invention.

Die members 22 include side clamps 74 on the top wall thereof forclamping bottom web member 70b during upper and lower run conveyance.Such side clamps 74 are associated with side clamp release mechanisms 76including release shafts 78, heads 80, and springs 82. The operation ofside clamp release mechanism 76 will be described more fully withreference to operational station D of the present apparatus. It shouldalso be mentioned that according to the particular size of the cheese 72deposited onto bottom web member 70b, a cavity filler 84 (FIG. 5) may beincluded at the bottom of die cavity 68 such that the bottom web member70b rests thereon during the various processing steps.

Now referring to FIGS. 3,4 and 5, the head 24 and operations forstations AB, and C will be described. At station A, the mechanism of themachine head 24 of the present invention provides an initial seal 113for the cheese package defined by web members 70a and 70b.

' effectively seal the cavities 68 during the action of heating surfaces91 on the preseal die members 92. (Rubber gasket 94 is not shown inFIGS. 6 and 9-1 1 for clarity but is presumed to be a part of thestructure shown in those figures.) The presealing mechanism furtherincludes bushing member 96 with operating shaft 98 disposed therethroughand spring 100 disposed about shaft 98 within bushing member 96 in orderto provide an automatic return action for the heat transfer mechanism.

Also at station A, pressure pad 102 operates to fix the seal 113 made bythe initial or preseal mechanism. Pressure pad 102 is operated by meansof a mechanism similar to that used in providing initial seal 113 andincludes shaft 104 mounted in bushing 106, with return action beingprovided by means of spring 108.

The actions of the initial seal mechanism and the pressure pad mechanismare simultaneous so that at any one time, four pack-ages are processedwith two receiving an intial seal (designated by areas 113 in FIG. 4)and two others receiving pressure from the pressure pad to fix theinitial seals, all at station A of the head mechanism.

Also, it may be seen clearly in FIGS. 4 and 5 that dies 22 define knifeholes 197 for facilitating the action of knives 194 as will be describedhereinafter.

Moving to station B, chamber 1 10 is lowered to cover and finally sealthe cheese packages. Thus, a final seal is provided in the areasdesignated 1 12 on FIG. 4 at station B to produce a complete seal 1 13(FIG.4). As previously described, the initial seal had accomplishedsealing of the areas designated 113 on FIG. 7 at station A. Prior tofinal sealing at station B a vacuum is drawn within the package chamberdefined by the package structure 28 and carbon dioxide with a Freontracer is introduced therein at station B for purposes of leak detectionas will be described hereinafter.

Introduction of the carbon dioxide with freon and final sealing areaccomplished after evacuation asshown particularly in FIGS. 6-8 whereinchamber 110 houses apparatus for accomplishing all of such functions. Achamber linkage, generally designated 114 includes a main connector 116,to which arms 118, 120, 122 are rotatably attached by pins 124 or thelike. Arm 122 extends to operational connection with pin 47 (see FIG.1), pin 47 leading to cam follower 54 for operation by cam system 50.

Thus, by motion of such linkage through connector 116, and pin 117 headelement 130 operates the chamber mechanism, and the final seal mechanismis operated through shafts 132 and springs 134. Return of head element130 is accomplished by means of shafts 142 and springs 144. Heatingelement 136 is provided within hot plates 138 depending from which areheat seal surfaces 140.

A vacuum is drawn from the package chamber with cheese 72 therein alongthe fiow line 149a into channel 149 (FIGS. 6 and 8), and then intoconduit 1491) (FIG. 6).

Introduction of carbon dioxide with freon is accomplished throughconduits 146 into hollow side clamps 74 through conduit connector holes77 defined by side clamps 74. Referring particularly to FIG. 8, carbondioxide with freon is introduced in direction 148 through channel 146'into side clamps 74 and then continuing in direction 148 under the topweb member a by way of tracer inlet holes defined by side clamps 74.Thus, when final seal is accomplished of top and bottom web members 70a,70b above rubber gasket 94, the cheese package 28 will include not onlycheese but also carbon dioxide and freon in an evacuated packagechamber. Introduction of such carbon dioxide and freon is furtherenabled through channels defined by walls 152 under the side clamps 74(FIG. 7).

Operational connection of chamber with head 24 is provided by aconnecting mechanism generally designated 154 on FIG. 3. For instance,return of the chamber 110 is provided by means of spring 156 surroundingshaft 158. Thus, the mechanism of station B provides a complex motionwhereby chamber 110 is first lowered to the cheese packages beingprocessed by means of upward motion in direction 49 of pin 47. Themotion of pin 47 is transmitted to chamber 110 as a downward motion ofconnector 1 16 and a concomitant downward motion of pin 117. Dampedmotion of the heat seal mechanism is provided through arms 120, 118, andshafts 132 with springs 134. Between the bottoming time for chamber 110and the bottoming time for the heat seal mechanism the cheese package isevacuated through channel 149 and carbon dioxide and freon areintroduced to the cheese package by means of conduits 146 and channel146'.

Referring to FIG. 12 the evacuation is performed through conduit 149bunder control of solenoid 149a by means of package evacuation pump 1490.

The operation at station C, shown on FIG. 3 and FIGS. 9, 10 and 11, isprovided by a mechanism which includes station C leak detection chambermember 160. The function at station C is to provide a sequence of motionof the mechanism whereby strippers 174 are first brought down to thecheese packages 28, after which knives 194 partially sever the packages(into groups of two packages each) along cutting areas 195 of FIG. 4 andthen chamber 160 is brought down so that a vacuum can be drawn about thecheese packages. Thereby, traces of freon escaping from the packages anda defective seal thereof may be detected.

Referring particularly to FIGS. 9, 10 and 11, the leak detection unit,generally designated 162, includes chamber 160, chamber bushing 164 anda chamber return mechanism including return shafts and return springs172. The stripper mechanism includes strippers 174 and stripper rods176, the stripper rods 176 being biased against the package by springs178. Operation of the chamber is accomplished by arms 180 whose motionpins 182 move in slots 184. Connection to the chamber itself for arms180 is provided through plates 186 on which is fixedly mountedupstanding lugs 186'. Stripper plate 188 provides the main connectionfor the stripper mechanism with the main head mechanism and the chambermechanism Vacuum air outlet for the chamber is provided through conduits190(FIG.10) for performing the operation at station D as willhereinafter be described.

As shown in FIG. 3, proximate strippers 174 are pressure pads 192 andstripping knives 194 in order to present wrinkling of the webs duringthe cutting operation, pressure pads 192 being controlled by means ofshaft 196 and spring 198. The operation at station C will now bedescribed.

First strippers 174 are brought down to within oneleighth inch from thecheese packages 28. Such spacing is provided in spite of the urging ofsprings 178 downwardly in the orientation of the drawings of FIG. 9.Such spacing is maintained by the pressure of slots 184 against motionpins 182 as shown in FIG. 9. Arms 180 are pivoted at points 200 and arethereby connected to lugs 186'. Arms 180 are held immovable both by theaction of slots 184 and studs 173.

At this point, the head 24 begins to travel downward as shown in FIG.wherein after one-eighth inch of travel, the stripper plates 174 bottomat the cheese package with springs 178 in compression. Then the chambermechanism 162, arms 180 and studs 173 continue downward anotherfive-eighth inch until the chamber contacts the edge of the dies asshown in FIG. 10. Downward motion of arms 180 is guided by means ofslots 184. Thus, it may be seen in FIG. 10 that knives 194 are moved toa position that severs the packages at cutting areas 195 (see FIG. 4)into units of two cheese packages.

Moving to FIG. 11, the head continues to move downward anotherone-eighth inch thus equalling a total of seven-eighthsinch motion fromFIGS. 9-11. Motion of the head causes arms 180 to move upward in thecenter of the drawing of FIG. 11 as guided by slots 184. Such action isproduced by the downward motion of studs 173 at the outward extremitiesof arms 180 and the action of pivots 200. Chamber 160 is immobilized sothat springs 172 are in compression. Pivots 200 remain stationary butstuds 173 are coming down one-eighth inch thus pressing on arms 180. Themotion of arms 180 upwardly at the center of the drawing of FIG. 11causes upward motion of plates 188 and concommittent upward motion ofstrippers 174, thus compressing springs 178 to a greater extent than thecompression of such springs as shown in FIG. '10.

In sequence therefore, the strippers have started downwardly in FIG. 9so that knives 194 cut the packages and a chamber is formed about thecheese packages 28 for leak detection. The strippers are then brought upslightly in order to expose the areas 113' of package 28 finally sealedduring the operation at station B (see also FIG. 4). Chamber 160 stillseals the area around the packages so that a proper vacuum may be drawnthrough conduits 190 to the leak detection apparatus as will now bedescribed.

Referring to FIG. 12, it may be seen that the chamber l60is connected byconduit 190 to vacuum pump 210. A vacuum is thereby drawn from thechamber 160 and the evacuated chamber air is drawn to leak detectionsensor 212 as shown in FIG. 12. Such leak detection sensors are commonin the gas analysis field and include, as an example, a grid or the likewith electrodes for detecting the presence of certain electrons. In thiscase, since freon was introduced with the carbon dioxide into thepackage, the function of leak detector sensor 212 is to sense thepresence of Freon within the air drawn from chamber 160. An electricalsignal is thereby transmitted by electrical signal carrying means 214 toleak detector 216 when freon is present in the air evacuated fromchamber 160. It should be stated at this point that while the evacuatedair is being drawn through conduit 190, an air compressor source (notshown) is providing compressed air through conduit 218 and valve 221 forinsertion to chamber 160, thus to purge the air in chamber and also topurge the sensing unit 212, where a heated cathode-anode platinumelement may develop a coating if not oxidized by the purging air fromconduit 218.

As statedbefore, when Freon is detected by the sensing units anelectrical signal is sent to leak detector 216 (FIG. 12) which producesan electrical signal for a memory module 222. The action of the memorymodule is such that a delay is provided prior to the sending of a signalthrough relay 224 and solenoid 226 to air cylinder 228. The delay isequivalent to the time it takes for a package 28' shown on FIG. 12 tomove from station C to station D where final cutting will take place ifno signal has been transmitted by the memory module 222 as will beexplained hereinafter.

Referring nowto FIGS. 2 and 13-15 in connection with the flow diagram ofFIG. 12, generally, station D operates firstly to remove the packagefrom conveyor 16 and secondly to selectively cut the tandem units of twopackages 28b into individual packages 28. The mechanism of station Dincludes suction apparatus 250, side clamp release apparatus 252 andcutting apparatus 254. The suction apparatus comprises shafts 256surrounded by springs 258 and suction cups 260 as well as shaft mountingplates 40a extending from uprights 40 to slidably mount shafts 256.Furthermore, stop members 256a are fixedly attached to shaft 256 andbiased upwardly by springs 258.

The cutting apparatus includes heating element 264, cutting knives 266and knife carriers 268. Guide 270 is inserted to slot 197 of the packageunit in order to properly orient hot knives 266 for the cuttingoperation at areas 199 of package 28 (FIG. 4). The cutting apparatus isoperated by use of air cylinder 228 (shown on FIGS. 12 14) cylinder 228being controlled by solenoid 226.

The side clamp release apparatus, as hereinbefore described includes aplunger 274, which for all packages whether leaking or not, operates topush down on shafts 78 thus releasing side clamps 74 from their hold onthe package webs 70. Springs 82 operate to return the side clamps totheir normal position for travel in direction 61(FIG.1). Thus, sideclamps 74 may then be used with other cheese packages 28 in anothercycle of operations.

Both the suction apparatus and the cutting apparatus are moved toproximity of the cheese packages 28 on the lower run of the conveyorsystem by the mechanism shown most clearly in FIGS. 14 and 15. Suchproximity mechanism, generally designated 290 includes moving arms 38,49 connected to plates 40 and 45, respectively, the arms being pivotedat points 294 on the frame member 36 (FlG.1). Motion of the entire unitis as shown in FIGS. 14 and 15 with the inoperative position beingdepicted by ghost lines 254 and 40, respectively and the operativeposition by solid lines in those figures.

Thus, at station C, the suction apparatus is operative once during eachcycle as to each cheese package 28. Particular reference to FIG. 15indicates the withdrawn position of suction cups 260 by means of ghostlines 260. Thus, the removal mechanism is described as op- 9 erating bybringing upright 40 to its uppermost position, at which point thesuction cups 260 will attach to cheese package units 28 or 28b, as thecase may be. Withdrawal of the suction cups 260 to a position depictedby ghost lines 260 will cause the package units 28 or 28b to bedeposited upon belts 33 as the suction cups 260 are lowered between suchbelts 33. On the other hand, depending upon whether or not a signal isreceived from memory module 222, the cutting apparatus is operative. Ifno signal is received, the air cylinder receives compressed air fromconduits 302 (FIG. 12) through solenoid 226 and a cut is made. Solenoid226 is controlled by relay 224 and program unit 304.

It may be seen, particularly from FIG. 12, that program unit 304 alsooperates to control the gas flow through conduit 146 to station B bycontrolling solenoid 306 and such program unit 304 further operates tocontrol both solenoid 149d through electrical signal means l49e andsolenoid 221 through electrical signal means 220, thus controlling theflow of purging air for station C of the operation.

In order to provide a more complete understanding of the presentinvention, a typical sequence of operations will now be described for acheese package beginning at station A and flowing through stations B, C,and D for deposit on moving conveyors 308 in FIG. 2. By way of furtherexplanation, it should be understood at the outset of this descriptionthat tandem package units, shown in FIG. 2 as units 28b and single units28 are segregated by the layout of moving conveyors 308; that is, singleunits 28 flow in directions 30 on either of the moving conveyors 308,but the tandem units 28b will be deposited between moving conveyors 308into a reject depository.

Generally, the packaging process which may be performed by the abovedescribed apparatus involves five station operations: Firstly, aninitial operation including forming the package by use of top web member70a and bottom web member 70b. Bottom web member 70b is formed into apackage bottom by overhead pressure and underneath suction so that thebottom web member 70b conforms to the four unit die cavity 68. The upperweb member 70a is unformed and lies in a generally flat plane over thecheese which is loaded into the package bottom formed by the bottom webmember 70b. Furthermore, the bottom web member is held in place underside clamps 74 for travel throughout the various operation stations asdescribed herein.

Secondly, at station A, an initial seal 113 is provided between the topweb member 70a and the bottom web member 70b, so that an appropriateopening is left throughout the transverse central portion of the cheesepackage 28. Such initial sealing is accomplished by means ofa heat sealunit and a pressure pad, which are arranged at the leading edge of amachine head 24 in an apparatus as described herein.

Thirdly, at station B, the inside of the cheese package 28 is evacuatedthrough the spaces left unsealed during the initial sealing process atstation A. Immediately thereafter, carbon dioxide gas with approximatelyonehalf per cent Freon tracer in introduced through the same open areaof the package 28. The package is then finally and completely heatsealed as a preliminary step to leak detection at the following stationC.

Fourthly, at station C, strippers are brought down against cheesepackage 28 and knives are used to cut the packages into units of twoalong cut lines 195 as shown in FIG. 4. Cross cuts are also made at thattime partially through the center of cheese package 28 along a lineperpendicular to the bisecting cut of the cheese package. Also atstation C, a chamber is lowered to seal the ambient area around thefinally sealed cheese package 28. A vacuum operates continuously tocarry into the vacuum line any trace of carbon dioxide with Freon tracerthat might exist in the sealed area. That is, if any Freon has escapedfrom the sealed package, it may be then sensed by appropriate apparatusas shown in FIG. 12. Prior to the completion of leak dectection vacuum,the strippers are raised slightly above the package in order to fullyexpose all of the seal lines for the package. In this way, since leaksare most likely to occur at or near seal lines, the leak detectionsensor is better able to perform its function.

Fifthly and finally, the package is inverted along the lower run 2012 ofthe conveyor system 16 for processing at station D. At this laststation, the package 28 undergoes a cutting step, a removal step and aseparation step. As background for this step, referring to FIG. 12,there are two possible situations for dealing with package 28 at stationD. Firstly, assuming that Freon had been sensed by leak detector sensor212 at station C, an electrical signal will be transmitted to the leakdetector electronics 216 for signaling memory module 222. Memory module222 then provides a positive signal to solenoid 226 thus inhibitingoperation of hot cutting knives 266 to sever the four unit cheesepackages along areas 199(FIG. 4) into four individual cheese packages28. Such inhibition is provided primarily by means of solenoid 226,after an appropriate delay long enough for package 28' to move from itssensed position at station C to a position at station D. Furthermore,such inhibition of the operation of air cylinder 228 leaves the fourunit cheese package in a condition whereby two tandem two package units28b are presented to the package removal suction apparatus.Particularly, with further reference to FIG. 12, program unit 304periodically initiates a closing of relay 224, thus periodicallyenabling transmission of a signal from memory module 222. When there isa signal from memory module 222 (a leak was detected at station C anddelay time has passed), the signal will be transmitted to solenoid 226,thus activating the solenoid and thereby closing the flow of compressedair through conduit 302. In this way, no air reaches air cylinder 228and, since air cylinder 228 activates the hot cutters, a cuttingoperation to provide individual, as distinguished from tandem, packageswill not take place. It should be understood that associated with memorymodule 222 is a means for delaying the transmission of a signal bycomponents well known in the art such as shift register means and thelike.

On the other hand, if the leak detection sensor 212 does not sensefreon, no electrical signal is propagated to solenoid 226. Thus, cuttingby knives 266 will not be inhibited and four individual packages will beprovided for the removal suction apparatus.

In either event, suction apparatus 250 cyclically provides suctioncontact between suction cups 260 and four inverted cheese package units28 or 28b. Periodic contact as recited above is provided primarily forsuction cups 260 by means of the cam-activated motion of arms 38.

Removal of the various packages 28 and 28b deposits four packages ontobelts 33, which move the packages onto moving conveyors 308. Individualpackages 28 are then carried in directions 30. Tandem packages 28b,however, are too wide for moving conveyors 308 and are thereby depositedbetween such conveyors as shown in FIG. 2.

Thus, in accordance with the above description of an apparatus andmethod, a fully automatic, continuous packaging, preserving, leakdetection and sorting system is used to overcome difficulties heretoforeexperienced in the food processing industry. Four or more packages areprocessed at any one time by motion of such packages through a series ofprocessing stations.

What is claimed is:

1. An apparatus for vacuum packaging at a plurality of operationstations comprising a first operation station, a second operationstation, a third operation station, and a fourth operation station, saidfirst operation station including means for forming a packagestructhrough a chamber opening defined by'said second area of contactwhereby, at said third operation station, leak detection for suchpackage structure is accomplished by sensing said leak tracer substancein the proximity of said package structure after final sealing isprovided for said second area of contact by said final seal unit of saidsecond operation station, said third operation station further includingmeans for partially cutting said package structure in a transversedirection before leak detection, a leak detection chamber unit defininga leak detection chamber within which said finally sealed packagestructure is placed, conduit means connected to said chamber, vacuummeans operatively connected to said conduit means, compressed air meansoperatively connected to said conduit means, control means for operatingsaid compressed air means such that said leak detection chamber isevacuated by said vacuum means to detect the presence or absence oftracer substance within said leak detection chamber and said chamber ispurged by said compressed air means after said evacuation, said fourthoperation station including means for selectively cutting said finallysealed package structure completely in said transverse directiondepending upon said detection of the absence of tracer substance withinsaid leak detection chamber, means for transmitting information of saiddetection from said leak detection chamber to said means for cuttingcompletely, and removing means for removing packaging units from saidmeans for forming.

2. The invention according to claim 1 wherein said means of transmittingincludes a leak detection sensor, leak detection electronics, a memorymodule, a solenoid means and an air cylinder for operating said meansfor cutting completely, such that said leak detection sensor detects thepresence of tracer substance to provide an electrical signal to saidleak detector electronics, which in turn provides a signal for saidmemory module, said memory module providing a delay for said signalequivalent to the time necessary for said sealed package structure tomove from said third operation station to said fourth operation station,after which said memory module controls said solenoid means to inhibitoperation of said air cylinder.

3. A method for vacuum packaging of perishable 1. partially sealing saidmembers to each other leaving openings therebetween; c. In a secondstation: 1

l. evacuating the space defined between said partially sealed members;

2. introducing to said space a tracer substance;

and,

3. thereafter completely sealing said members to each other;

d. In a third station:

1. partially cutting said members in a transverse direction andcompletely cutting said members in a longitudinal direction to formtandem package units of two packages each;

2. enclosing tandem package units in a leak detection chamber;

3. evacuating said chamber; and

4. sensing the presence or absence of tracer substance in said chamberto detect leaking of said units;

e. In a fourth station:

1. selectively cutting said members to completely out said members in atransverse direction, said selection depending upon the presence orabsence of said tracer substance; and

2 depositing said packages onto a conveyor unit for further processingof those packages for which the absence of tracer was sensed.

4. a method according to claim 3 including the step of transmittinginformation containing the sensed presence or absence of tracersubstance to a means of controlling said fourth station cutting step.

1. An apparatus for vacuum packaging at a plurality of operationstations comprising a first operation station, a second operationstation, a third operation station, and a fourth operation station, saidfirst operation station including means for forming a package structurehaving a package bottom and a package top in general contact with eachother to define a package chamber and first and second areas of contact,and means for partially sealing said package bottom to said package topin said first area of contact therebetween, said second operationstation including means for evacuating said package chamber having achamber unit overlying said package structure, means for introducing aleak tracer substance to said package chamber, and a final seal unitwithin said chamber unit, such that a leak tracer substance isintroduced to said package through a chamber opening defined by saidsecond area of contact whereby, at said third operation station, leakdetection for such package structure is accomplished by sensing saidleak tracer substance in the proximity of said package structure afterfinal sealing is provided for said second area of contact by said finalseal unit of said second operation station, said third operation stationfurther including means for partially cutting said package structure ina transverse direction before leak detection, a leak detection chamberunit defining a leak detection chamber within which said finally sealedpackage structure is placed, conduit means connected to said chamber,vacuum means operatively connected to said conduit means, compressed airmeans operatively connected to said conduit means, control means foroperating said compressed air means such that said leak detectionchamber is evacuated by said vacuum means to detect the presence orabsence of tracer substance within said leak detection chamber and saidchamber is purged by said compressed air means after said evacuation,said fourth operation station including means for selectively cuttingsaid finally sealed package structure completely in said transversedirection depending upon said detection of the absence of tracersubstance within said leak detection chamber, means for transmittinginformation of said detection from said leak detection chamber to saidmeans for cutting completely, and removing means for removing packagingunits from said means for forming.
 2. The invention according to claim 1wherein said means of transmitting includes a leak detection sensor,leak detection electronics, a memory module, a solenoid means and an aircylinder for operating said means for cutting completely, such that saidleak detection sensor detects the presence of tracer substance toprovide an electrical signal to said leak detector electronics, which inturn provides a signal for said memory module, said memory moduleproviding a delay for said signal equivalent to the time necessary forsaid sealed package structure to move from said third operation stationto said fourth operation station, after which said memory modulecontrols said solenoid means to inhibit operation of said air cylinder.2. depositing perishable items into said bottom members; and, 2.depositing said packages onto a conveyor unit for further processing ofthose packages for which the absence of tracer was sensed.
 2. enclosingtandem package units in a leak detection chamber;
 2. introducing to saidspace a tracer substance; and,
 3. overlying said items with a pluralityof package top members thus to form packages; b. In a first station: 3.thereafter completely sealing said members to each other; d. In a thirdstation:
 3. evacuating said chamber; and
 3. A method for vacuumpackaging of perishable items during a plurality of station operationscomprising the steps of: a. In a preliminary station:
 4. a methodaccording to claim 3 including the step of transmitting informationcontaining the sensed presence or absence of tracer substance to a meansof controlling said fourth station cutting step.
 4. sensing the presenceor absence of tracer substance in said chamber to detect leaking of saidunits; e. In a fourth station: